UPDATE: Thanks to Linda Leinen for pointing out that what I thought were mollusks are barnacles, which in spite of their shells turn out to be crustaceans. Who’d have expected that? Steve Gingold had mentioned barnacles in his comment but I’d mistakenly thought he was referring to the dark objects.

I laughed to see them described as “troublesome pests.” In fact, the single most loathsome job in the boatyard is scraping barnacles off the bottom of a boat before repainting. I helped with the job once, and quit halfway through. Like the housekeeper who doesn’t do windows, I don’t do boat bottoms.

Scrapers still are the best first step for a boat too large to be pulled from the water and flipped. Barnacles are so hard, sanding them would be like trying to sand concrete. It’s much better to get a blade under them, scrape them off, then deal with the residue by pressure-washing and sanding.

Also, barnacles are terribly messy, full of water and general nastiness. Even the roughest floor-grade sandpaper can’t cope with that. When a boat’s pulled from the water, you want to get them off as soon as possible, since they get even harder once they dry. Even if you tried to sand them off, you’d be faced with flying, wet, sharp debris.

That brings up another important issue. barnacles are sharp as knives. Every year people get scratched by them — even the lightest scratch on a foot or arm — and end up being affected by two very dangerous bacteria: Vibrio vulnificus and Mycobacterium marinum.

Vibrio is particularly bad on the Gulf coast, and can be picked up by coming in contact with the bacteria while in the water, or by activities like cracking crabs, fishing, or messing around barnacle-covered pilings or boat bottoms. It can move fast, and can lead to loss of limbs, or even death. There’s an informative first-person account written by a physician here.

As long as I’m into this, the best treatment for cuts, scrapes, or pin-prick injuries (like an embedded fishhook) isn’t hydrogen peroxide. It’s a 1:10 bleach/water solution. I carry a gallon of the solution in the trunk of my car, and when I have a close encounter of the barnacle kind, I take precautions.

I had no idea how much trouble barnacles cause and how hard to remove they are. From what you say about their sharpness, people wanting to swim at Little Manly Beach had best be careful where they walk. The etymologist in me noticed that the species name vulnificus means ‘wound-maker’ (you can find the fancy English word vulnific in a few dictionaries). I understand why you go around with your bleach solution.

And now I know that his grandfather, Erasmus, was noted for racey poetry in a text titled “Zoonomia,” written in 1794. His motto appears to have been Ex omnia conchis, and the Darwin-Wedgewood family crest contains three shells. Charles’ son Francis once asked another child, “where does you father do his barnacles?”

“It was not until 1830 that it was realized that barnacle were crustaceans. Since they were shelled creatures, naturalists had considered them mollusks akin to mussels and limpets. John Thompson followed the embryology and metamorphosis of barnacles and determined by their developmental characteristics that they were actually closely aligned to the crustaceans.”

Barnacles bring back pleasant childhood memories for me, Steve. I spent many hours exploring the rocks and pools of a small coastal town. You’ve made artwork here out of photographing sea creatures. Great compositions.

I’m doubly glad: you consider the photographs artwork and they remind you of pleasant times from your childhood. You can tell I was thrilled with all the little details I found at Little Manly Beach, and I’m sure that if I’d had more time I would have found plenty more to photograph along that section of coast.